I'm a forest biologist who occasionally has to control pests in built-up and environmentally sensitive areas.
This is a .410 shotgun using .45 Colt cases with 6 grains of whatever shotgun powder I'm loading my 12ga target loads with at the time, a fiber over-powder wad, the case filled with steel shot topped by a thin cardboard overshot wad sealed by wax. Just make sure you store them in a cool place, not your truck's glove compartment.
Quiet and works great within 15 yards on small pests. At greater distances providing I'm on dry ground, I use regular lead 410 loads. Even in an antique, provided the barrel is in good condition, pressure is the least of my worries with these. Not enough shot weight.
